Pseudomorph Goethite After Marcasite | Prophecy Stone | 30.2 gr | Farafra Oasis, Egypt | SO24 L3-6 Shape: Oval Faceted Cut

Shape:  Oval Faceted Cut

superb shape and good size

Origin: Ukraine

Shape: Round Cut

Pseudomorph Goethite After Marcasite | Prophecy Stone | 30.2 gr | Farafra Oasis, Egypt | SO24 L3-6 Shape: Oval Faceted CutPseudomorphs are mineral specimens that have the external shape of one mineral but are composed of another. The pseudomorph goethite after marcasite forms when marcasite is exposed to oxidizing conditions and starts to oxidize and break down. As the marcasite breaks down, goethite replaces it in the crystal structure, preserving the shape of the original marcasite crystal. The resulting specimen appears as a marcasite crystal, but is actually composed